Scotland’s Rocks and Fossils Handling Collection · Scotland’s rocks and fossils handling...

National Museum of Scotland Teachers’ Resource Pack

Scotland’s Rocks and Fossils

Handling Collection


Scotland’s rocks and fossils handling collection

Teachers notes

Welcome to the National Museum of Scotland.

Our Scotland’s Rocks and Fossils handling collection contains 22 real

specimens from our collections and we encourage everyone to enjoy

looking at and handling them to find out more.

This resource is linked to the Early People and Restless Earth galleries and can be used as part

of your visit to those galleries.

These notes include:

Background information about metamorphic, igneous and sedimentary rocks.

Background information about fossils.

Tips on how to recognise different types of rocks and fossils.

Details about each object.

Ideas for questions, things to think about and to discuss with your group.

NMS Good handling guide The collection is used by lots of different groups so we’d like your help to

keep the collection in good condition. Please follow these guidelines for

working with the artefacts and talk them through with your group.

1. Always hold specimens over a table and hold them in two hands

2. Don’t touch or point at specimens with pencils, pens or other sharp objects

3. Check the specimens at the start and the end of your session

4. Please report any missing or broken items



Contents Igneous rocks 1. Basalt

2. Granite

3. Andesite lava with agates

4. Jasper

5. Obsidian

Sedimentary rocks 6. Sandstone

7. Limestone

8. Shale

Metamorphic rocks 9. Lewisian Gneiss

10. Schist

11. Garnet mica schist

12. Iona marble

13. Coal

Animal fossils 14. Chain coral

15. Solitary horn coral

16. Colonial coral

17. Fish Armour, Asterolepis maxima

18. Gigantoproductus giganteus

19. Mammoth tooth

20. Ammonite

Plant fossils 21. Leaf

22. Scale tree bark



Geology and Palaeontology Geology is the study of our planet, Earth. It tells us:

How the Earth was made

What it is made of

How it has changed over time

Palaeontology is the study of fossils. It tells us:

About ancient life on Earth

The conditions on Earth in the past

Scotland’s landscape in the past

The landscape of Scotland began to form billions of years before the arrival of humans and has changed dramatically over time to become the landscape we know today. The rocks and fossils that we will look at in this resource are the result of these processes of change.

Around 500 million years ago, parts of Scotland formed part of a continent called Laurentia which existed on the equator. This continent moved north over millions of years.

Scotland and England joined together around 410 million years ago when the ocean that separated them gradually closed up.

During its journey across the face of the Earth, the land we now know as Scotland has experienced extreme cold, desert heat and major volcanic activity.

During the time period when dinosaurs roamed the earth, Scotland was either hilly ground or submerged beneath shallow tropical seas.

For the last 60 million years Scotland, and indeed Europe as a whole, has been very slowly drifting away from North America.

Over a period of 2.5 million years, Scotland has been covered in ice at least five times. The last Ice Age in Scotland ended 10,000 years ago.



Scotland’s landscape today Scotland can be separated into five main geological parts:

1. The North West

2. The Central and Northern Highlands west of the Great Glen Fault

3. The Central and Grampian Highland

4. The Midland Valley

5. The Southern Uplands

These areas are separated by big faults or breaks in the Earth’s crust. Most of these faults can still be

identified in the landscape.

Each part of Scotland has its own distinctive rock types, some of which you will look at in this resource.

Scotland’s landscape is transient and can change at any time. Changes are slowly taking place today and

Scotland might look completely different in another few hundred million years!



Igneous rocks

Igneous rocks are formed when molten (melted) rock cools and hardens.

The word ‘igneous’ comes from the Latin word for fire.

Molten rock which erupts from a volcano is called lava. Molten rock beneath the Earth’s crust is called

magma.

When molten rock cools above ground, it cools quickly and small crystals form inside it. This is called

‘extrusive’ rock.

When molten rock cools below ground, it cools more slowly, allowing larger crystals to grow. This is

called ‘intrusive’ rock.

How to recognise igneous rocks:

1. They often show an interlocking crystal structure.

2. You can often see individual crystals in them.

3. Some extrusive igneous rocks have ‘vesicles’ or holes in them. These form as gas tries to escape from the molten rock as it cools.

The next five rocks listed are all igneous rocks.



1. Basalt Basalt is an igneous rock that erupted as lava.

The tiny crystals in this specimen show that it cooled down quickly.

Arthur’s Seat and Castle Rock in Edinburgh, North Berwick Law in East

Lothian and Tinto Hill in South Lanarkshire were all volcanoes from which lava would have erupted.

Basalt can sometimes form columnar joints like those at Fingals Cave

on Staffa. As the erupted lava cools, it can shrink and crystallises into the hexagonal columns.

If the lava is erupted under water the outer ‘skin’ cools and can then be

inflated by more lava forming what is known as a pillow lava.

The minerals which make up basalt are pyroxene, plagioclase and

olivine. Basalt is the finest grained of the mafic (rich in magnesium and iron) igneous rocks. The coarse grained rock from this group is gabbro, it cools and crystallises much more slowly under the surface of the earth.

See

Look at how the black rock appears to sparkle. This is because of the crystals in it.

Touch

Compare it to the metamorphic marble specimen. The two pieces are the same size. Which is heavier?

Think

Most of the basalt in the world forms under the ocean. This means it is less commonly found than other rocks because it is harder to get.

Basalt columnar jointing from

Fingal’s Cave, Staffa.

Example of pillow lava

under the sea.



See

The pink colour of the rock

with grey and black crystals.

Touch

Can you feel the difference

in texture between stone and the crystals?

Think

What qualities do you think

granite has that makes it

popular for buildings and

interior fittings like floors

and kitchen counters?

2. Granite Granite is an igneous rock which formed below ground.

Granite can take millions of years to cool so the crystals in it

can grow very large.

Granite is a good material for building because it is very

strong. Many houses in Aberdeen are built from granite which

gives the city its nickname—’The Granite City’.

Granite colours can vary from pink to grey depending on how

much of each mineral is present. There are various individual

component minerals of granite in this specimen. These are

quartz, plagioclase feldspar, K (potassium) feldspar,

muscovite, biotite and amphibole. How many different

minerals can you see?

Granite is coarse-grained because it cools so slowly—the

minerals found in granite can also be found in finer grained

rocks which have crystallised faster, see andesite as an

example.



See

The reddish rock sparkles

slightly when it catches the

light. The light picks out the

individual crystals in the

bigger mass.

Touch

The smooth agates inside the rougher surfaced lava.

Think

How do the minerals that

make the agates manage to

get through this rock to fill

the bubbles?

- Through tiny/miniscule

cracks and fissures caused

by stress in the ground and

rock.

3. Andesite lava with agates This lava erupted from a volcano millions of years ago.

It is from Angus in Scotland. This means there must have

been volcanic activity in that area a long time ago, just like

Edinburgh.

The lighter blobs within the rock are agates. When the lava

erupted, it would have had lots of bubbles of air inside it

(vesicles). Over millions of years, these bubbles were filled

with water moving through the rocks. This water reacted with

silica from the rock and formed varieties of quartz which

crystallises to form the agates. These varieties include

chalcedony and onyx which create beautiful colours and

patterns in the rocks.

This rock is reddish in colour due to the type of minerals that

it is made from. It has a similar mineral composition to the

granite, but it also contains more of a mineral called augite.



See

The beautiful red and

yellow stripes.

Touch

Feel the weight of the

stone. Do you think it is

heavy or light?

Think

Jasper is often used in

jewellery because of its

beautiful colour and

because it can be shaped

and polished.

4. Jasper This piece of jasper is from the Campsie hills in central

Scotland.

You can’t see individual crystals in the jasper. It is made up of

a variety of quartz called chalcedony, where the crystals are

so small that they can only be seen through a microscope.

Jasper comes in a variety of colours including red (like this

specimen), yellow, and occasionally green. Red jasper

contains high quantities of iron.

Jasper often contains minerals which give it interesting

patterns and stripes.



See

The shiny glass-like ap-pearance of the rock

Touch

It feels smooth like glass

but if you move your

finger slowly over it, you

can feel the ridges in the

rock.

Think

Why do you think it looks

like glass?

- Because it forms quickly

without any crystals.

5. Obsidian Obsidian rock forms when lava cools very, very quickly,

usually In water.

When lava cools very quickly, there is no time for crystals to

grow and it forms this glass-like rock.

Obsidian is often called ‘volcanic glass.’

It was very precious to ancient civilisations and is still used

today to make jewellery and ornaments.

Even today surgeons sometimes use obsidian blades in

scalpels for the most delicate of surgeries as it is much

sharper than stainless steel.



Sedimentary rocks 70% of all the rocks on the Earth’s surface are sedimentary rocks.

Sedimentary rocks are formed on the Earth’s surface, below seas, rivers, lakes and deserts.

Tiny fragments of rock, sand, mud, minerals and the remains of plants and animals are washed

away or blown to a new place. Over time, these fragments accumulate eventually form layers of

sediment.

The sedimentary layers can harden into rock in two ways: they can be compacted by pressure from

above or ‘glued’ together by minerals dissolved in water.

Sedimentary rocks can often contain fossils.

How to recognise sedimentary rocks:

1. They sometimes have grains that are cemented together.

2. They can be lightweight as they are not very dense.

3. They are often light-coloured.

4. You can often see layers in them where lots of sediments have been deposited over millions of

years.

5. They might contain fossils.

The next three rocks listed are all sedimentary rocks.



6. Sandstone Sandstone is formed when layers of sand are compressed and bound

together by natural cement.

Sandstones vary in colour depending on the properties or colours of the

original sand. Grey sandstone is made from sand originating from a

marine environment, underwater; and red sandstone forms from iron rich

sand such as those found in some deserts.

Some sandstones have patterns in them which tell us about the

environment they were deposited in. Sometimes you can make out

individual layers which criss-cross over each other. This tells us about

the currents created by wind or water when the sand was deposited.

Sometimes, you can also see squiggly lines in the layers. These can be

caused by water quickly flushing in and disturbing the neat layers of

sand. Ancient creatures can also disturb the layers by burrowing into

them. This is called bioturbation.

See

The red colour of this

piece. Where do you think

it came from?

Touch

You can feel the grains of

sand in the stone.

Think

When you visit the

Scotland galleries in the

National Museum of

Scotland look at the

outside of the building. It

is covered in gold Moray

sandstone.



7. Limestone Limestone is made from the remains of shells and sea

creatures such as coral.

This means limestone is full of the mineral calcite. This is a

form of calcium mixed with carbon and oxygen.

This rock formed around 340 million years ago at a time when

Scotland was a tropical reef.

Limestone is easy to distinguish from other sedimentary rocks

because it will react with acid. Therefore, geologists usually

carry around a little bottle of weak acid to pour onto rocks. If

the rock fizzes it must be limestone.

See

There are two kinds of

coral fossils in this

limestone; spaghetti and

horn. Can you identify

each kind of fossil?

Touch

Feel the difference in

texture between the stone

and fossils.

Think

Because limestone has

lots of cracks and joints,

water can seep down

through them and form

‘limestone pavements’,

‘limestone scars’ and

‘limestone sinkholes' in

the ground.

Fab fact!

Limestone can also form

around your hot tap if you

live in a 'hard water' area,

because the calcium

carbonate can only

remain in solution in cold

water.



8. Shale This piece of shale is from Loanhead quarry, Beith,

Strathclyde in Scotland.

Shale is made up of compressed layers of clay and fine

grained silt.

It is a type of mudstone which was deposited in a marine

environment such as the sea floor, the bottom of a lake, or a

river flood plain. Organic material can also be deposited within

the layers of clay and silt. This is what can make this type of

rock very important. Shale forms when the organic

compounds break down and fossilise.

The fossilised organic material makes the shale rich in carbon,

which is a fossil fuel that we burn to get energy.

Oil can be extracted from shale.

See

The layers which make

up the shale.

Touch

The smooth surface of

the rock. It is very fine

grained.

Think

Can you think of any other rock that we use for energy production?


Metamorphic rocks Metamorphic rocks are rocks which have been changed by heat and pressure deep

underground in the Earth’s crust.

The minerals in metamorphic rocks can be changed into new minerals.

Imagine baking a cake; the original ingredients look very different once they are baked. The same thing happens with metamorphic rocks.

We can sometimes tell what the original rock was - for example, limestone becomes marble - but if the rock has been highly metamorphosed, this can become more difficult.

How to recognise metamorphic rocks

1. They have layers in the rock. This is called ‘foliation’.

2. They often have bands of light and dark colours.

3. They can have large grains that interlock with each other.

The next five rocks listed are all metamorphic rocks.




See

The black and white

stripes in the rock

Touch

Feel the surface of the

rock. This smoothness is

caused by weathering.

Think

The Earth itself is 4.55

billion years old so this

rock was created when

the Earth was still young.

9. Lewisian Gneiss This is one of the oldest types of rock in the world. It is approximately 3

billion (3000 million) years old.

It is found in North West Scotland and is named after the Isle of Lewis

in the Outer Hebrides.

Gneiss has been changed so much that it is difficult to tell what the

original rock was like.

Gneiss is usually black and white or pink and is often stripy.

Gneiss is pronounced ‘nice’



See

The layers of crystal that

follow the line of the folds.

Touch

The smooth texture of the

rock.

Think

Why do you think this

specimen is so shiny?

Is it shiny because it

contains lots of a mineral

called ‘mica’.

10. Schist This piece of schist is about 1 billion years old.

It comes from Scourie in North West Scotland.

Schist is a rock that has been heated and compressed. This piece of

schist has been folded like paper by the immense heat and pressure

deep in the Earth’s crust.

The word schist comes from an ancient Greek word and means ‘to split’.

Schist has thin layers called ‘foliation’.



11. Garnet mica schist Schist is a rock that has been heated and compressed,

This rock is about 1 billion years old.

This rock is made up of different minerals such as garnets, mica,

quartz and feldspar.

Garnets are dark red stones. These are semi-precious stones that

are often used in jewellery.

Mica is a shiny mineral which exists in several forms. The most

common forms are muscovite mica which is colourless and clear,

and biotite mica which is brown. Can you see them both in this

example?

The grey parts of the rock are made of quartz and feldspar.

See

The different components

of the rock

Touch

You can feel the thin

layers of micas round the

edges.

Think

Why do you think garnets

are considered precious?


Touch

The smooth texture of the

marble. Even the unpol-

ished sides are very

smooth. This is because

the crystals that make it

are very small and tightly

packed.

Think

The City Chambers in

Glasgow has the largest

marble staircase in the

world.

See

The beautiful white calcite

and tremolite and pale

green forsterite.


12. Iona marble The age of this piece of marble is debated by geologists.

Originally when it came to the museum, it was thought to

be 450 million years old. Recent research has suggested it

is much older, as much as 1.4 billion years old.

It comes from the isle of Iona in the Inner Hebrides, of

Scotland.

Marble is limestone that has been heated and com-

pressed.

Marble is a very hard rock that polishes well and is often

used for ornaments and statues.



13. Coal Coal formed between approximately 300-325 million years ago,

during the Carboniferous period, when large tropical forests grew.

When the forest trees and plants died, they fell into swamps and

were covered by more plants and sediments.

Over time, the plant material did not rot - it turned into peat. Heat

and pressure then finally turned it to coal as it was compressed

over millions of years.

Coal burns easily and is one of our main ‘fossil fuels’.

See

The layers in the coal.

Touch

Why isn’t this specimen

making your hands dirty

like most pieces of coal?

It has been painted with a

special product which

locks in the coal dust.

Think

If coal is often found in

Scotland, what does this

tell us about our climate

millions of years ago?

Scotland once had a

warm, tropical climate.



Fossils Fossils are the preserved remains of ancient life. Trace fossils are the

evidence of ancient animals such as footprints, coprolites (fossilized

dinosaur poo!) and burrows.

Fossils are usually found in sedimentary rocks as they are destroyed by

the heat that creates igneous and metamorphic rocks.

Animal and plant remains turn into fossils because:

1. The remains are actually quickly buried by mud or sand. This protects

them from the weather, predators and scavengers.

2. Sediment builds up on top of the remains and ensures that they will stay

buried for a long time.

3. They were not subjected to too much heat or pressure which would

have destroyed them.

Most fossils form under water as more than 70% of Earth’s surface is

covered in water.

Here is one example of how a fossil can be formed:

1. A dead animal falls to the bottom of a sea, river or lake.

2. The soft parts of the animal - the skin and muscles - rot away leaving

the harder bones and teeth, which are buried as sand and mud is

washed over them.

3. Over time, the hard parts are buried deeper by the sediment. The

weight of the layers of sediment causes it to compact and turn to hard

rock.

4. Millions of years later, the rock is brought to the surface by mountain

building processes. It is then weathered by wind and rain and the fossil

is exposed.

Fab fact!

Fossils that are millions of

years old are clues to how life

has evolved and adapted to

changing environments over

very long periods of time.



See

The chain pattern formed

by the living coral.

Touch

Use your fingers to trace

the pattern from the top

down the edges of the

fossil.

Think

Can you think of a place

where corals grow today?

The best known is the

Great Barrier reef in

Australia.

Coral fossils Corals are marine animals with a sac-like body (polyp), mouth,

tentacles and skeleton.

Only the skeleton survives as a fossil.

The corals may be solitary (living by themselves) or colonial (many

joined together).

Before they were fossilised, these corals would have lived in warm,

shallow, tropical seas and fed on plankton, like the corals we can

see today.

14. Chain coral This piece of coral is about 450 million years old.

It is known as a chain coral because it looks like the links of a

chain.

Each ‘link’ in the chain was where an individual coral animal lived.

As this coral fossil was made up of many individual coral animals, it

is a colonial coral.

This coral fossil belongs to an extinct type of corals, called the

‘Tabulate corals’. It is called Halysites.



15. Solitary horn corals These corals are between 320 and 340 million years old.

They are called horn corals because the shape of the

skeleton is like a horn.

They are called solitary corals as each contained only one

coral animal.

They could vary in size from a few millimetres wide to 14

centimetres wide and grow up to 1 metre long

They belong to an extinct type of coral called the ‘Rugose

corals’. The word rugose means wrinkled or corrugated.

See

Two of the horn coral

specimens have been cut

and polished. You can see

lines which form the

structure of the skeleton

which form a circular

pattern and also run

lengthways down the

Touch

Touch the uncut specimen

- can you feel the

‘wrinkles’ in it?

Think

Can you think of anything

that looks like this today?



See

The honeycomb pattern in

each individual coral.

Touch

The bumps on the outside

that follow the form of the

pattern on the inside.

Think

As this coral was found in

Bathgate, what does this

tell us about that area of

Scotland 320 million years

ago?

16. Colonial coral This piece of coral is about 320 million years old and comes from

Bathgate in Scotland.

This coral was made up of many individual coral animals forming a

honeycomb pattern

Like the other coral fossils it is believed to have lived in warm,

clear, shallow seas.



See

The shape and size of the

armoured plate. This fish

didn’t have scales but was

covered in armour. This

plate comes from the back

of it’s head.

Touch

The texture - how does

this armour feel different

to modern day fish

scales?

Think

Different species of fish

have been living on Earth

for about 400 million

years. Why do you think

they have lasted so long?

Animal fossils

17. Fish Armour, (Asterolepis

maxima) This fossil is about 360 million years old and was found in Nairn

in the Highlands.

At this time part of the Highlands and Orkney were covered by

a large lake.

It is the dorsal plate (head shield) from a primitive armoured fish

which is called Asterolepis maxima.

These fish fossils are now only found preserved in Upper Old

Red Sandstone.

From their remains we can tell that these fish grew to the length

of about 1 metre.



See

Look at the shape - what

does it remind you of?

Touch

Feel the ribs in the shell

that helped anchor the

creature in the sand.

Think

What did the shell do?

Think of animals today

that have shells and why

they have one?

18. Gigantoproductus

giganteus This is the fossil of an ancient type of shellfish, a brachiopod

It was the largest of the brachiopods and grew to over 30

centimetres wide.

Some brachiopods lived in shallow waters close to the shore or

near reefs. This creature’s size, weight and ribbed shell would

have prevented it from being washed too far away.

Brachiopods were nearly wiped out 250 million years ago and are

now only found in cold, deep parts of the ocean (over 40 meters

down).



See

The size of this part of the

tooth. Mammoths had four

grinding teeth.

Touch

The massive grooves in

the tooth to help the

mammoth chew and break

up their food.

Think

Mammoths had molar

teeth as they were

herbivores - they ate only

plants. Animals such as

lions have large, sharp

‘canine’ teeth, and molars

adapted to slicing, as they

are carnivores and eat

meat. We are omnivores

and have both molars and

canines to chew plants

and also tear meat.

19. Mammoth tooth The shape of this tooth tells us that mammoths were plant eaters.

Meat eaters have sharp teeth for tearing flesh – mammoths had

ridged teeth to grind up the coarse plants they ate.

This piece is only a fragment of the actual tooth. A whole tooth

would have been about five times bigger!

Mammoths lived during the last Ice Age when temperatures were

much lower than they are today. They were protected from the

cold by a thick covering of hair.

Some mammoths have been found frozen in permafrost in Siberia

so we have a very good idea what they looked like. Prehistoric

men also painted pictures of them in caves.



See

The spiral shape of the

shell

Touch

The fossil is very heavy.

Do you think it would have

been this heavy when the

creature was alive?

Think

What was the shell for?

It protected the soft body

of the ammonite from

predators.

20. Ammonite Ammonites were ancient relatives of the squid and octopus. They

lived in the sea between 200 and 65 million years ago. They became

extinct around the same time as dinosaurs.

Ammonites belong to a group of animals known as cephalopods.

They can be recognised by their coiled shells which contained a

series of chambers.

We think ammonites moved by jet propulsion, expelling water through

a funnel-like opening to propel themselves in the opposite direction.



See

You can still see the veins

in the leaf.

Touch

The volcanic ash is very

fine grained so could

preserve the tiny intricate

details of the leaf.

Think

Do you think this leaf

looks the same as or

different to the leaves on

trees today?

Plant fossils

21. Leaf in volcanic ash This is part of a leaf preserved in fine grained volcanic ash. It is

about 58 million years old and was found on the Isle of Mull.

At this time there were active volcanoes on Mull and Skye, in Scot-

land.

Leaf fossils can help build up a picture of the variety of plant life

that was living at the time.



See

The shape of the pattern

on the bark.

Touch

It is still very rough, just

like normal tree bark.

Think

Take a rubbing from a tree

bark and compare it to

this. How does it differ?

22. Scale tree bark This fossil is about 320 million years old. It comes from a time

when Scotland was covered in tropical forests and swamps.

The scale tree got its name because the diamond shaped pattern

on its bark looked like fish scales.

Scale trees could be enormous, growing to heights of more than

35 meters with their trunks measuring over 1.7 meters in diameter.

Scale tree fossils are often found in in the sediments above and

below coal seams.

This fossil tree is called Lepidodendron sp.

The scale tree is the extinct relative of the lycopods (club mosses).

These type of plants are still alive today but are a lot smaller.

Scotland’s Rocks and Fossils Handling Collection · Scotland’s rocks and fossils handling...

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